Dryas integrifolia : Entire-leaf Mountain Aven

Scientific Name:

Kingdom: Plantae

Division:

• Tracheophyta (vascular)
• Spermatophyta (seed bearing)
Angiospermae (enclosed seed)

Class: Dicoteldonae (two seed-leaves)

Family: Rosaceae (Rose Family)

Genera: Dryas (Mountain Avens) (Gk. Drus = Oak; referring to the resemblance of the leaves of some species to oak leaves.)

Species: integrifolia (Lat. integer=whole, entire + folium=leaf = entire leaved; referring to the smooth leaf edges.)

Synonym(s): D.sylvatica

English Name(s):

Entire-leaf Mountain Aven, Entire-leaf Dryas, White Dryas/Mountain Avens

First Nation Names:

Structure:

• Low mat-forming undershrub.
• Branches freely rooting.

Leaves:

• Leathery, tardily deciduous (falling) or evergreen.
• Petioled (on a stalk).
• Lanceolate-oblong distinctly broadest below middle, cordate (heart-shaped), truncate (flat), or cuneate (rounded) at base.
• Blades 8-45mm lonh by 3-12 mm wide. 3 times longer than wide.
• Margins entire (smooth) or with a few teeth in lower half, often more or less revolute (curled under).
• Dark green, shiny, and glabrous (hairless) above, white tomentose (wooly) below.
• With stipules (appendages) rising from leaf axils, linear-lanceolate in shape, tomentose (wooly).

Reproductive Parts:

• Flowers perfect (bisexual), with regular symmetry, scapose (on leafless stem), and normally solitary.
• Hypanthuim (recepticle) saucer shaped.
• Sepals and petals 8-10.
• Petals white.
• Stamens (male parts) and pistils (female parts) numerous.

Seed:

• Style persisting and becoming much-elongated and plumose in fruit.
• Fruit is an achene (nutlet).

Not to Be Confused With:

• The other Dryas (Mountain Avens). Dryas octopetala (Eight-petalled Mountain Aven) can be distinguished by its toothed not smooth leaf margins. Dryas drummondii (Yellow-flowered Mountain Aven) can be distinguished by its yellow petals and broader leaves.

Physiology:

• Dryas (Mountain Avens) are superbly adapted to the rigours of the exposed areas where they grow. The tough roots are deeply anchored and their nodules contain nitrogen fixing bacteria.
• The leaves with their waxy coating and wooly undersides are designed to conserve moisture and in summer and shed ice in winter.
• The feathery styles permit wide dispersal of seeds.
• The parabolic shape of the flowers which face the sun, focuses the suns energy on the pistil (female parts) heating it up by up to 3.6 C. The warmer temperatures attract pollenating insects whose body temperatures when basking in the flowers may exceed the ambient air temperature by 5-15 C.

Life Cycle:

• Perennial

Seasonal Cycle:

• Leaves tardily deciduous (falling).
• Some leaves are evergreen and will survive the winter.
• Some patches still blooming mid-July.

Animal Uses:

Habitat:

• Are a pioneering species in areas recently exposed by receding glaciers.
• Liking calcareous sites.
• An ubiquitous (everywhere) pioneer species in rocky or gravbelly places such as river flats.
• Less common in tundra or heath where not long surviving competition from more aggressive tundra plants.

Modern:

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• Flowers and achene plumes (seed feathers) produce a vivid green dye.
• Is the floral emblem of NWT

Medicinal:

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Traditional Gwich'in:

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Traditional Other:

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